Some known waterproof connectors include a so called wire seal or all-in-one rubber seal inside a connector housing to prevent water and the like from entering the housing from outside. The wire seal has contact insertion passageways thereon along positioned corresponding to respective passageways in the connector housing, and is adopted to ensure a waterproof function by allowing wires connected with contacts to be pressed tightly against the edges of inner perimeters of the contact insertion passageways when the contacts are inserted into the passageways through the contact insertion passageways. The circuit board that connects with the waterproof connector has various specifications. The number of passageways formed on the connector is decided correspondingly to the largest number of contacts required among the specifications of the circuit board. As a result, the contacts are not necessarily inserted into all the passageways for some circuit boards to connect with. In that case, the contact insertion passageways corresponding to hollow spaces, the passageways that the contacts are not inserted into, are closed with plugs, so called dummy plugs, to ensure the waterproof function. It is inefficient, however, for an operator to insert the dummy plugs into the hollow spaces of the connector housing with many hollow spaces.
In view of the aforementioned circumstances, Japanese Patent No. 3174261 and Japanese Patent Application Laid-Open No. 2006-324161 propose covers with built-in dummy plugs which have dummy plugs in locations corresponding to the hollow spaces. The covers have dummy plugs projecting therefrom that fit in all the respective contact insertion passageways of the wire seal. The covers are adopted to form the contact insertion passageways by allowing jigs to punch the dummy plugs corresponding to the passageways in which the contacts are to be inserted since the dummy plugs have thin-walled parts.
In Japanese Patent No. 3174261 and Japanese Patent Application Laid-Open No. 2006-324161, a step of using jigs to break through the dummy plugs corresponding to the passageways in which the contacts are to be inserted is necessary after production of the covers with built-in dummy plugs. It is efficient of an operator in performing this step, in fact, it is as inefficient as the step of inserting the dummy plugs into the hollow spaces one by one. Specifically, in Japanese Patent No. 3174261, perforating pins are attached to respective threaded passageways of an upper base (jig), and then the upper base attached with the perforating pins is pressed onto a lower base (jig) so that cutting edges break through unnecessary dummy plugs. When a connector housing has fewer hollow spaces, an operator has to attach more perforating pins to the connector housing, which is much more troublesome than to insert the dummy plugs into the hollow spaces one by one.
Since the covers with built-in dummy plugs of Japanese Patent No. 3174261 and Japanese Patent Application Laid-Open No. 2006-324161 require significant force to simultaneously break through the dummy plugs, only experienced operators can perform the step of breaking through the dummy plugs without having the jigs slip off.
In addition, the covers with built-in dummy plugs of Japanese Patent No. 3174261 and Japanese Patent Application Laid-Open No. 2006-324161 waste material by disposal of the broken-through dummy plugs.